Effective Media for Immobilising and Isolating Radionuclides from Aqueous Nuclear Wastes: Reaction Products of Bone Char and Uranyl Ions
- Geosciences Advisory Unit, National Oceanography Centre, European Way, Southampton, SO14 3ZH (United Kingdom)
- Brimac Carbon Services Ltd, Dellingburn Street, Greenock PA15 4TP, Scotland (United Kingdom)
The reaction of uranyl ions with bone char under a variety of laboratory conditions leads to products (e.g. uranium modified bone char) that are effective in incorporating and retaining radionuclides. The products are highly insoluble and are compositionally analogous to natural uranium-bearing minerals found in the supergene environment. A calcium uranium oxyhydroxide, similar to becquerelite is produced when bone char reacts with uranyl ions at elevated temperatures and pressures under mildly acidic conditions (pH{approx}4). Under more acidic conditions (pH{approx}3), a compound similar to phosphuranylite forms whilst in the presence of excess phosphate, a compound similar to chernikovite is produced. Radiotracer studies show the various products incorporate a wide range of elements including Am, Cd, Ce, Co, Cs, Eu, Mn, Pd, Pu, Ru, Sm, Sn, Tc, Y, Zn and Zr. Four uptake mechanisms are inferred to occur and vary according to the element. These are ionic substitution into the uranyl compound or hydroxyapatite and surface adsorption onto hydroxyapatite or carbon. This makes the modified bone char materials generally applicable for the adsorption of a wide range of diverse species. Once incorporated/adsorbed, the radionuclides are not readily leached under neutral or mildly acidic conditions thereby providing a stable solid phase. The wide range of elemental species adsorbed / incorporated into the UMBC, the relative ease of producing these compounds and their stability indicates that there is considerable potential for the application of this material in the isolation of radionuclides from aqueous nuclear waste streams and the stabilisation of these wastes during storage and disposal. Possible long-term storage options could include packaging of the dried phosphatic powders, grouting with cement, or incorporation into phosphatic or borosilicate glass. (authors)
- Research Organization:
- WM Symposia, Inc., PO Box 13023, Tucson, AZ, 85732-3023 (United States)
- OSTI ID:
- 21208719
- Report Number(s):
- INIS-US-09-WM-06257; TRN: US09V1030079506
- Resource Relation:
- Conference: Waste Management 2006 Symposium - WM'06 - Global Accomplishments in Environmental and Radioactive Waste Management: Education and Opportunity for the Next Generation of Waste Management Professionals, Tucson, AZ (United States), 26 Feb - 2 Mar 2006; Other Information: Country of input: France; 10 refs
- Country of Publication:
- United States
- Language:
- English
Similar Records
Groundwater uranium stabilization by a metastable hydroxyapatite
300 Area Uranium Stabilization Through Polyphosphate Injection: Final Report